Electrostatic reproduction involves an electrostatically-formed latent image on a photoconductive member, or photoreceptor. The latent image is developed by bringing charged developer materials into contact with the photoconductive member. The developer materials can include two-component developer materials including carrier particles and charged toner particles, for example, for “hybrid scavengeless development” having an image-on-image development. The developer materials can also include single-component developer materials including only toner particles. The toner particles adhere directly to a donor roll by electrostatic charges from a magnet or developer roll and are transferred to the photoconductive member from a toner cloud generated in the gap between the photoreceptor and the donor roll during the development process. The latent image on the photoconductive member can then be transferred (i.e., printed) onto a media substrate such as a paper sheet.
During the printing process, one challenge is to reliably and efficiently move charged toner particles from one surface to another surface, e.g., from carrier beads to donors, from donors to photoreceptors, and/or from photoreceptors to papers, due to toner adhesion on surfaces. For example, distributions in toner adhesion properties and spatial variations in surface properties of the adhered toner particles (e.g. filming on photoreceptor) lead to image artifacts, which are difficult to compensate for. Conventional solutions for compensating for these image artifacts include a technique of image based controls. However, such technique mainly compensates for the artifacts of periodic banding. To compensate for other artifacts such as mottle and streaks, conventional solutions also include a mechanism of modifying the toner material state using maintenance procedures (e.g., toner purge), but at the expense of both productivity and run cost.
Thus, there is a need to overcome these and other problems of the prior art and to provide a roll member having distributed actuators and sensors for providing sufficient short-range force to overcome the toner adhesion.